CN108110740B - A kind of dc circuit breaker failure protection method - Google Patents
A kind of dc circuit breaker failure protection method Download PDFInfo
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- CN108110740B CN108110740B CN201810019260.1A CN201810019260A CN108110740B CN 108110740 B CN108110740 B CN 108110740B CN 201810019260 A CN201810019260 A CN 201810019260A CN 108110740 B CN108110740 B CN 108110740B
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- breaker
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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Abstract
The invention discloses a kind of dc circuit breaker failure protection methods, comprising the following steps: DC line protection movement issues dc circuit breaker trip signal, while starting breaker fail protection;It is delayed after Δ T1, acquires DC bus-bar voltage UbWith line side voltage Ul, and calculate the average value E of the two difference in the Δ T2 timek;Judge whether to meet Ek> Eset;If it is satisfied, then determining that breaker successfully disconnects, protection is returned;If conditions are not met, then determining that breaker disconnects not successfully, breaker fail protection movement, remaining connected breaker of Xiang Yuben bus issues trip signal, and Xiang Benduan inverter issues block signal.The method of the present invention is not needed using the information inside dc circuit breaker, and the voltage for only relying on busbar voltage and dc circuit breaker line side can reliably differentiate whether breaker successfully acts.
Description
Technical field
The present invention relates to direct current transportation technical field of relay protection, in particular to a kind of dc circuit breaker failure protection side
Method, the dc circuit breaker failure protection suitable for the DC grid using dc circuit breaker.
Background technique
The generations of electricity by new energy such as wind energy, solar energy have the characteristics that intermittent, randomness, and when large-scale grid connection can be to tradition
Electric power networks generate impact, reduce the economy and reliability of power grid.Multi-terminal HVDC transmission based on flexible DC transmission technology
System and DC grid can efficiently solve this problem.Meanwhile with the progress of mixing Circuit breaker technology and to direct current system
The raising of reliability requirement, in route two sides, the DC grid scheme of configuring direct current breaker becomes preferred embodiment.Such
In DC network, when network Single Point of Faliure, no longer needs entire direct current system of stopping transport, but by dc circuit breaker isolated fault area
Domain saves from damage and perfects part.Currently, the method that academia has been presented for a large amount of rapid line protections.Other than quick main protection, it is
Guarantee reliability, it is also necessary to configure corresponding Fast Operating Backup Protection, when breaker tripping due to all kinds of, be lost by breaker
Clever protective separation fault zone, prevents failure from spreading to network rest part.
In traditional AC system, the size that breaker fail protection generally passes through detection line current judges that failure is
No removing, and the delay of long period is set to avoid the actuation time of main protection.In DC grid, the failure of breaker
Protection can also judge whether breaker disconnects by detecting the size of line current.However the method institute based on current detecting
It takes time longer, guard time window length need to be greater than line current and decay to the threshold value time below.If breaker is failed
It disconnects, in guard time window, line current easily rises to quite serious degree, even results in the change of current of non-faulting region
It stands locking, reduces the reliability of direct current system.And the failure protection scheme based on circuit breaker internal information measurement, although detection
Speed is higher, but this method depends on circuit breaker design and internal information amount, does not have versatility.It is therefore proposed that it is a kind of quickly,
The wide dc circuit breaker failure protection method of applicability is very necessary.
Summary of the invention
The purpose of the present invention is to overcome the shortcomings of the existing technology and deficiency, provides a kind of dc circuit breaker failure protection side
Method prevents line fault after dc circuit breaker failure from cannot cut off in time and fault coverage is caused to expand.This method does not need
Using the information inside dc circuit breaker, only rely on busbar voltage and dc circuit breaker line side voltage can reliably differentiate it is disconnected
Whether road device successfully acts.
The purpose of the present invention is realized by the following technical solution: a kind of dc circuit breaker failure protection method, including with
Lower step:
4) DC line protection acts, and issues dc circuit breaker trip signal, while starting breaker fail protection;
5) it is delayed after Δ T1, acquires DC bus-bar voltage UbWith line side voltage Ul, and calculate the two difference in the Δ T2 time
Average value Ek;Wherein, Δ T1 is setting delay time, need to be greater than the intrinsic actuation time of installed dc circuit breaker;ΔT2
For the time window length of mean value calculation;
6) judge whether to meet Ek> Eset;If it is satisfied, then determining that breaker successfully disconnects, protection is returned;If discontented
Foot, then determine that breaker disconnects not successfully, breaker fail protection movement, remaining connected breaker of Xiang Yuben bus, which issues, jumps
Lock signal, Xiang Benduan inverter issue block signal;Wherein, EsetFor breaker fail protection criterion threshold value.
Preferably, Δ T2 can use 2-3ms in step 2).
Preferably, in step 2), EkCalculation formula are as follows:
Wherein N is the number of sampling points in Δ T2, Ub(i) the busbar voltage instantaneous value of n-th of sampled point, U are indicatedl(i) table
Show the line side instantaneous voltage of n-th of sampled point.
Preferably, in step 3), EsetFor breaker fail protection criterion threshold value, setting principle is metallicity in area
Minimum E after breaker successfully disconnects under failurekValue is multiplied by safety factor, it may be assumed that
Eset=krel·Ek,min
Wherein, krelFor safety factor, numerical value is less than 1.
This method is using the voltage difference in DC bus side and line side as breaker failure differentiation amount.Line fault hair
After life, when breaker does not disconnect, this voltage difference is the pressure drop on route current-limiting reactor, due to line impedance, bridge arm electricity
Anti- equal partial pressure effect, this voltage difference will be less than route voltage rating;When breaker successfully disconnects, in dc circuit breaker
Arrester is serially accessed to the circuit, this voltage difference will include current-limiting reactor pressure drop and arrester voltage, due to arrester voltage compared with
Height, this voltage difference also will be maintained at higher level, until stablizing to route voltage rating.Utilize voltage difference described above
Feature, can differentiate whether dc circuit breaker successfully disconnects.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1, there is universality: without circuit breaker internal information, only relying on bus bar side voltage and line side voltage
It completes breaker failure to differentiate, therefore is suitable for different types of dc circuit breaker.
2, guard time window is short: compared to the method for discrimination based on the magnitude of current, realizing that breaker failure differentiates using voltage
Required actuation time is shorter, without waiting for electric current complete attenuation, is conducive to promptly isolate failure.
3, protection philosophy is simply easily realized, the way being averaged is conducive to improve reliability.
Detailed description of the invention
Fig. 1 is the flow chart of embodiment method.
Fig. 2 is the DC network model of embodiment.
Fig. 3 is the breaker fail protection voltage measurement point schematic diagram of embodiment.
Specific embodiment
Present invention will now be described in further detail with reference to the embodiments and the accompanying drawings, but embodiments of the present invention are unlimited
In this.
Embodiment 1
A kind of dc circuit breaker failure protection method, the flow chart of this method are as shown in Figure 1.In the present embodiment, use
PSCAD/EMTDC simulation software constructs DC network model, as shown in Fig. 2, DC network is mainly by four converter stations, direct currents
Route and dc circuit breaker etc. are constituted, and all converter stations are all made of the inverter of semi-bridge type submodule, using pseudo- bipolar wiring side
Formula, rated direct voltage are ± 320kV.DC line is using overhead transmission line according to frequency model.When inherently cut-offfing of dc circuit breaker
Between be 2ms.The voltage measurement point schematic diagram of breaker fail protection is as shown in figure 3, protection sample frequency is 10kHz.
Dc circuit breaker failure protection the following steps are included:
1) DC line protection acts, and issues dc circuit breaker trip signal, while starting breaker fail protection;
2) after postponing set time Δ T1, busbar voltage U is calculatedbIn line voltage distribution UlDifference, and calculate it in Δ T2
Average value Ek;
It wherein, is 2ms by the intrinsic switch off time of breaker in this present embodiment, Δ T1 is set as in the present embodiment
2.5ms;Δ T2 is set as 2ms, and thus N is equal to 20.
3) judge whether to meet Ek> Eset;If it is satisfied, then determining that breaker successfully disconnects, protection is returned;If discontented
Foot, then determine that breaker disconnects not successfully, breaker fail protection movement.
Route L14 is respectively set away from intereelectrode short-circuit failure occurs at 1 side different distance of inverter, time of failure is equal
For t=0.71s.The power line main protection that DC line L14 is located at 1 side of inverter is out of order in t=0.712s detection, to breaker
B14 issues trip signal, and starts breaker fail protection.After postponing 2.5ms, busbar voltage and line voltage distribution are acquired, is calculated
Busbar voltage UbWith line voltage distribution UlAverage value of the difference in 2ms.Each failure is provided with breaker and successfully disconnects and break
Road device disconnects two kinds of situations, E not successfullykOutput the results are shown in Table 1.
Table 1
E for same failure it can be seen from the simulation result of table 1, after dc circuit breaker disconnectionkIt is disconnected much larger than direct current
E when road device does not disconnectk.E after breaker disconnects when due to head end failurekValue is minimum, is 706.5kV, takes the safety factor to be
0.8, then protecting threshold value is 565.2kV.The differentiation of dc circuit breaker failure is carried out according to threshold value, for the failure of different location
It can be correctly completed breaker failure differentiation, worked well.
For overhead transmission line, when short trouble occurs or along with transition resistance.Therefore to the certain model of head end fault setting
The transition resistance enclosed, with the E after examining the tolerance transition resistance ability of this method, breaker successfully to disconnectkOutput result
As shown in table 2.With the increase of transition resistance, E it can be seen from output resultkValue is declined.This guard method is up to
Action message is remained under 300 Ω transition resistances, tolerance transition resistance is functional.
Table 2
Transition resistance/Ω | 20 | 50 | 100 | 150 | 200 | 250 | 300 |
Ek/ disconnect | 648.9 | 623.6 | 584.0 | 601.6 | 604.3 | 591.8 | 578.1 |
The above embodiment is a preferred embodiment of the present invention, but embodiments of the present invention are not by above-described embodiment
Limitation, other any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present invention,
It should be equivalent substitute mode, be included within the scope of the present invention.
Claims (3)
1. a kind of dc circuit breaker failure protection method, which comprises the following steps:
1) DC line protection acts, and issues dc circuit breaker trip signal, while starting breaker fail protection;
2) it is delayed after Δ T1, acquires DC bus-bar voltage UbWith line side voltage Ul, and calculate the flat of Δ T2 time interior the two difference
Mean value Ek;Wherein, Δ T1 is setting delay time, need to be greater than the intrinsic actuation time of installed dc circuit breaker;Δ T2 is flat
The time window length of mean value computation;
3) judge whether to meet Ek> Eset;If it is satisfied, then determining that breaker successfully disconnects, protection is returned;If conditions are not met, then
Determine that breaker disconnects not successfully, breaker fail protection movement, remaining connected breaker of Xiang Yuben bus issues tripping letter
Number, Xiang Benduan inverter issues block signal;Wherein, EsetFor breaker fail protection criterion threshold value, setting principle is area
Minimum E after breaker successfully disconnects under interior metallicity failurekValue is multiplied by safety factor, it may be assumed that
Eset=krel·Ek,min
Wherein, krelFor safety factor, numerical value is less than 1.
2. dc circuit breaker failure protection method according to claim 1, which is characterized in that Δ T2 can use 2- in step 2)
3ms。
3. dc circuit breaker failure protection method according to claim 1, which is characterized in that in step 2), EkCalculation formula
Are as follows:
Wherein N is the number of sampling points in Δ T2, Ub(i) the busbar voltage instantaneous value of n-th of sampled point, U are indicatedl(i) the is indicated
The line side instantaneous voltage of n sampled point.
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CN108110740B (en) * | 2018-01-09 | 2019-10-18 | 华南理工大学 | A kind of dc circuit breaker failure protection method |
CN109119975B (en) * | 2018-08-22 | 2020-04-28 | 许继集团有限公司 | Direct current system and failure protection method of circuit breaker in starting process of direct current system |
CN112531660A (en) * | 2020-12-17 | 2021-03-19 | 国网辽宁省电力有限公司铁岭供电公司 | Method for protecting circuit breaker from failure in direct current power grid |
CN113013857B (en) * | 2021-05-08 | 2022-07-08 | 国网江苏省电力有限公司镇江供电分公司 | 220kV inner bridge connection transformer substation circuit breaker failure relay protection method |
CN116599005A (en) * | 2023-05-04 | 2023-08-15 | 天津大学 | Secondary acceleration fault isolation method after direct current breaker failure |
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CN104022494A (en) * | 2014-06-21 | 2014-09-03 | 中国能源建设集团广东省电力设计研究院 | Alternating current and direct current coordinating protection method and device for flexible high voltage direct current transmission converter station circuit breaker |
CN106849031A (en) * | 2017-04-06 | 2017-06-13 | 华北电力大学 | A kind of alternating current-direct current mixing micro-capacitance sensor coordinating protection coordinated scheme |
CN107221915A (en) * | 2017-05-17 | 2017-09-29 | 南京南瑞继保电气有限公司 | A kind of method of dc circuit breaker failure protection |
CN108110740A (en) * | 2018-01-09 | 2018-06-01 | 华南理工大学 | A kind of dc circuit breaker failure protection method |
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Publication number | Priority date | Publication date | Assignee | Title |
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CN104022494A (en) * | 2014-06-21 | 2014-09-03 | 中国能源建设集团广东省电力设计研究院 | Alternating current and direct current coordinating protection method and device for flexible high voltage direct current transmission converter station circuit breaker |
CN106849031A (en) * | 2017-04-06 | 2017-06-13 | 华北电力大学 | A kind of alternating current-direct current mixing micro-capacitance sensor coordinating protection coordinated scheme |
CN107221915A (en) * | 2017-05-17 | 2017-09-29 | 南京南瑞继保电气有限公司 | A kind of method of dc circuit breaker failure protection |
CN108110740A (en) * | 2018-01-09 | 2018-06-01 | 华南理工大学 | A kind of dc circuit breaker failure protection method |
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